We are getting an AC/DC fridge in our next RV but it is a compressor type and DC does not use as much energy. A 3-way absorption type which we have now is used either propane or AC. We gave up on the DC way because it did not do the cooling as well and if you left it on DC for a short stop and forgot to convert it to propane it would drain a battery under two hours. If you have propane on board then a 3-way is the way to go. We had our fridge on our current RV on propane most all the time except when on shore power and only ran our 9 gallon propane tank down to 50% on our spring RV trip of 3 months. A propane fridge is very efficient. We used propane for a little bit of morning wakeup heating, hot water and cooking but not the generator.